Ultra or Endurance for 2 OCIs?

I understand. Gotta admit I’ve cut quite a few with louvers that tore.
Tearing media has nothing to do with the center tube using holes or louvers. Media tears when the pleat spacing is crazy wide and the media is weak and brittle and can't take any bending force from the dP across the pleats.
 
Media tears when the pleat spacing is crazy wide and the media is weak and brittle and can't take any bending force from the dP across the pleats.
OT, but this is what makes me wonder about Subaru specifying a 23psi bypass for some of their filters. Apparently Subaru also specs some media that is much stronger than that used in most other filters? Or, for whatever reason Subaru is OK with allowing filters to get much closer to destruction in order to keep the filters from going into bypass. I suspect there is a pretty hefty safety margin between the bypass setting and when the media breaks, for most filters. In any case, I am not wild about the louvers mainly because there seems to be a lot of variability in how well made they are, even from the same manufacturer. With holes you can see at a glance that all is well, while with louvers you have to make a judgment call if you get a chance to view them before you buy the filter. I don't like parts that require me to make inspections of them before using.
 
OT, but this is what makes me wonder about Subaru specifying a 23psi bypass for some of their filters. Apparently Subaru also specs some media that is much stronger than that used in most other filters? Or, for whatever reason Subaru is OK with allowing filters to get much closer to destruction in order to keep the filters from going into bypass.

OEM Subaru filters have a lot of media packed into a small filter, and have tight pleat spacing, which would help to allow a high bypass pressure setting. Subaru's specs for filter media area for these filters are typically 800 to 1100 square cm. This is more media area than pretty much aftermarket oil filter recommended for these engines.

The high bypass pressure setting and high media area are to ensure that the filters don't start bypassing before the oil pump does, since Subaru uses high flow oil pumps with high pressure relief settings.

The Royal Purple filter was the most restrictive filter in the Ascent Filtration test. If the FRAM Endurance is a re-badged Royal Purple, they can be expected to bypass regularly on a Subaru, even with warm oil. The Royal Purple filter in the test dropped 17 psi at a lower flow rate than most Subaru oil pumps are rated for, and it was also a much larger filter than those intended for a Subaru. That said, a 20-micron filter that bypasses some oil will still protect the engine better than a 50-micron OEM Tokyo Roki filter that never bypasses oil.
 
The Royal Purple filter was the most restrictive filter in the Ascent Filtration test. If the FRAM Endurance is a re-badged Royal Purple, they can be expected to bypass regularly on a Subaru, even with warm oil. The Royal Purple filter in the test dropped 17 psi at a lower flow rate than most Subaru oil pumps are rated for, and it was also a much larger filter than those intended for a Subaru. That said, a 20-micron filter that bypasses some oil will still protect the engine better than a 50-micron OEM Tokyo Roki filter that never bypasses oil.
Here are the dP curves from the Ascent tested filters. All were subjected to a constant flow rate with the same test dust concentration in the test oil. I'd have to go dig around in the Ascent thread to see what flow rate and effective viscosity this test oil was at. As the filters go from new to full loaded the dP increases as they load-up until they hit the point where the test was stopped - defined as an increase of 8 PSI of dP over the new filter dP starting point. Some filters took more time to load up and achieve the +8 psi dP before the test was stopped, and therefore had a higher holding capacity.

Also, regarding your bold text in quote above. Not sure what you're looking at to say there was a "drop of 17 psi" with the RP. All you can glean from the test data is that the RP has a higher initial dP when new, and the dP increased faster (even though it's efficiency wasn't the best in the bunch) as it loaded up to when the +8 psi dP defined the end of test. Since it took less time for the RP to achieve the +8 psi dP, then it's holding capacity reflects that. Same happened to the ACDelco Ultraguard.

If the RP had lower holding capacity, then how can Fram rate it for 25K miles when the Ultra is rated for 20K miles? This may also be a clue that the Fram Endurance isn't really the same exact media as the Royal Purple. Of course, we wouldn't know for sure without side-by-side tests like done with these filters.

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Here are the dP curves from the Ascent tested filters. All were subjected to a constant flow rate with the same test dust concentration in the test oil. I'd have to go dig around in the Ascent thread to see what flow rate and effective viscosity this test oil was at. As the filters go from new to full loaded the dP increases as they load-up until they hit the point where the test was stopped - defined as an increase of 8 PSI of dP over the new filter dP starting point. Some filters took more time to load up and achieve the +8 psi dP before the test was stopped, and therefore had a higher holding capacity.

Here are the dP vs flow curves for the filters before they are loaded with dirt. The test viscosity is 13.5 cST, equivalent to a 5W30 at around 90 degrees C.

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The Royal Purple has a dP of around 465", or 17 psi, at 49 L/min. Subaru oil pumps will typically flow 55-85 L/min near redline, and they will use a smaller, more restrictive filter than the one tested as well, so they may start bypassing at less than half the rated oil flow, and well before the oil pump starts limiting flow by going into pressure relief (assuming that the RP filter has a typical bypass setting).

If the RP had lower holding capacity, then how can Fram rate it for 25K miles when the Ultra is rated for 20K miles? This may also be a clue that the Fram Endurance isn't really the same exact media as the Royal Purple. Of course, we wouldn't know for sure without side-by-side tests like done with these filters.
There's no industry standard that equates miles of use to grams of capacity, so manufacturers' claims could vary even if their filters perform identically. A study in another thread showed that 10% of oil filters used in small displacement engines will load up at a rate of more than 1 gram per 2,000 km, so even the FRAM Ultra in the Ascent test would clog in less than the rated 32,000 km on at least 10% of engines. The mileage rating is a judgment call, and FRAM is probably okay with a certain percentage of their filters becoming clogged at that mileage. They probably also have a bunch of disclaimers, such as not exceeding the vehicle manufacturer's recommended interval.
 
Here are the dP vs flow curves for the filters before they are loaded with dirt. The test viscosity is 13.5 cST, equivalent to a 5W30 at around 90 degrees C.

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The Royal Purple has a dP of around 465", or 17 psi, at 49 L/min. Subaru oil pumps will typically flow 55-85 L/min near redline, and they will use a smaller, more restrictive filter than the one tested as well, so they may start bypassing at less than half the rated oil flow, and well before the oil pump starts limiting flow by going into pressure relief (assuming that the RP filter has a typical bypass setting).
Not so sure about any Subaru oil pump actually sending 85L/min (which is 22.4 GPM) through the engine's oiling system. What Subaru claims that? Also, the oil pump flow specs in the Subaru manuals seem to be unregulated flow, meaning with no restriction on the output side, and no pump pressure relief. Would they really flow that rate through the engine without hitting pressure relief first? Has anyone in the world actually verified the actual flow volume on an engine to see if it matches the manual specs?

As I've said before, anyone with a Subaru with the high flow oil pump that puts out around 13-14 GPM at near redline should just use the OEM filter or an aftermarket filter with a higher bypass valve setting specifically for the Subaru applications if they are worried about filter bypassing.

There's no industry standard that equates miles of use to grams of capacity, so manufacturers' claims could vary even if their filters perform identically. A study in another thread showed that 10% of oil filters used in small displacement engines will load up at a rate of more than 1 gram per 2,000 km, so even the FRAM Ultra in the Ascent test would clog in less than the rated 32,000 km on at least 10% of engines. The mileage rating is a judgment call, and FRAM is probably okay with a certain percentage of their filters becoming clogged at that mileage. They probably also have a bunch of disclaimers, such as not exceeding the vehicle manufacturer's recommended interval.
Of course, just like any big oil filter manufacturer, they say to follow the vehicle manufacture's maintenance recommendations. On a few vehicles like Hondas, it might be possible to get very near the up to 20K mile rating if you follow the A/B maintenance schedule and go by the OLM for oil and filter changes.
 
We need a Jim Allen from the Subaru world to set up a test vehicle that measures oil flow and pressure before and after the filter! A couple of things make me highly suspicious that the 23psi bypass is critical. One is that if you plug your particular Subaru into the Fram part selector they recommend one with a lower bypass. In my case I am using the XG6607 at 13psi. Obviously, FRAM thinks that is good enough. Two is that manufacturers are notorious for speccing the same part for multiple cars. They don't want to stock more parts than they have to. Maybe the 23psi is or was needed for early turbos for example, so they just said we'll use that filter for the non-turbos too. Frankly, I think it is rather crazy all the different filter sizes with different specs out there. A third reason is just my seat of the pants observation that I have never had an engine failure and have put a lot of miles on cars that saw nothing but the cheapest cheapy lube oil changes with whatever no-name filter they put on, and at way over the mfg recommended OCI. Today's cheapest oils and filters are good enough to just about guarantee 200K of trouble free engine endurance. I suspect better oil and filters are an improvement, but the gains are not easily noticed by us average drivers.
 
Not so sure about any Subaru oil pump actually sending 85L/min (which is 22.4 GPM) through the engine's oiling system. What Subaru claims that? Also, the oil pump flow specs in the Subaru manuals seem to be unregulated flow, meaning with no restriction on the output side, and no pump pressure relief. Would they really flow that rate through the engine without hitting pressure relief first? Has anyone in the world actually verified the actual flow volume on an engine to see if it matches the manual specs?
The 6-cylinder 2015+ Outbacks spec 83 L/min. The WRX specs 60 L/min at 6700 rpm and 57 psi with oil at 120 degrees C (around 6.5-7 cST). The pressure relief is 102 psi. Doing the math, the oil pump's pressure relief will start to activate at 6700 rpm when the oil is 15 cST. The FRAM Ultra from the Ascent test would have a dP of 18 psi in these conditions, and for the smaller XG9688 for this engine, it would probably be around 25 psi if it didn't have a bypass. Any of the filters in the test would start bypassing well before the pump is in pressure relief, if they had a typical bypass pressure.

I see no reason to doubt Subaru's oil pump specs. If they didn't have such high flow rates, there would be no need for the oil filters with a high bypass pressure and high filter media area.

We need a Jim Allen from the Subaru world to set up a test vehicle that measures oil flow and pressure before and after the filter! A couple of things make me highly suspicious that the 23psi bypass is critical. One is that if you plug your particular Subaru into the Fram part selector they recommend one with a lower bypass. In my case I am using the XG6607 at 13psi. Obviously, FRAM thinks that is good enough. Two is that manufacturers are notorious for speccing the same part for multiple cars. They don't want to stock more parts than they have to.

It seems that aftermarket filter manufacturer's just don't care to design filters specific to engines that have unique requirements. The same filter is recommended by FRAM for the two engines previously mentioned, despite the fact that the one engine flows 40% more oil and specs an OEM filter with 45% more filter media area.

I'm fine with this, since occasional bypassing of oil seems to have no meaningful effect on engine wear, based on studies comparing bypass filtration to full flow filtration. If the filter is bypassing because it is clogged, that is a different story. Still, on a Subaru I would favour an oil filter with less restriction that the Royal Purple.
 
The 6-cylinder 2015+ Outbacks spec 83 L/min.
That seems a bit crazy when you think about it. 83L/min is 21.9 GPM. If the sump is only 5 qts (1.25 gal), then the entire sump volume would be cycled through the engine 17.5 times every minute - or, once every 3.4 seconds. Sounds totally unrealistic to me, because if that was actually the case the oil level in the sump would most likely be below the oil pickup and oil starvation would occur. Subaru seems to have an over-obsession with oil flow through the engine, lol.

The WRX specs 60 L/min at 6700 rpm and 57 psi with oil at 120 degrees C (around 6.5-7 cST). The pressure relief is 102 psi. Doing the math, the oil pump's pressure relief will start to activate at 6700 rpm when the oil is 15 cST. The FRAM Ultra from the Ascent test would have a dP of 18 psi in these conditions, and for the smaller XG9688 for this engine, it would probably be around 25 psi if it didn't have a bypass. Any of the filters in the test would start bypassing well before the pump is in pressure relief, if they had a typical bypass pressure.
That's why I keep saying if anyone is paranoid about the filter bypassing on a Subaru, then just get the OEM filter.

I see no reason to doubt Subaru's oil pump specs. If they didn't have such high flow rates, there would be no need for the oil filters with a high bypass pressure and high filter media area.
There are other reasons why some manufacturer's use a higher bypass valve setting. Higher flow resistance of the filter or trying to cut-down on cold start bypass events, etc.

It seems that aftermarket filter manufacturer's just don't care to design filters specific to engines that have unique requirements. The same filter is recommended by FRAM for the two engines previously mentioned, despite the fact that the one engine flows 40% more oil and specs an OEM filter with 45% more filter media area.
Some filter makers do specify a different filter with a higher bypass valve setting for Subarus.
 
Here are the dP vs flow curves for the filters before they are loaded with dirt. The test viscosity is 13.5 cST, equivalent to a 5W30 at around 90 degrees C.

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Think I brought this up before in another thread in these discussions. This is a medium sized PureOne (PL14006) that Purolator tested for dP vs Flow. The test viscosity was 11.5 cSt which is basically 5W30 at 100C. Slightly thinner than the 13.5 cSt, but if the PureOne below was flowing 13.5 cSt oil the curve wouldn't be raised up much.

Using the same units as the Ascent data, his PureOne is 163 in-H2O (5.9 PSI) at 49.2 L/min (13 GPM). This curve on the Ascent graph would be way below all of those curves, even if corrected from 11.5 to 13.5 cSt.

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Think I brought this up before in another thread in these discussions. This is a medium sized PureOne (PL14006) that Purolator tested for dP vs Flow. The test viscosity was 11.5 cSt which is basically 5W30 at 100C. Slightly thinner than the 13.5 cSt, but if the PureOne below was flowing 13.5 cSt oil the curve wouldn't be raised up much.

Using the same units as the Ascent data, his PureOne is 163 in-H2O (5.9 PSI) at 49.2 L/min (13 GPM). This curve on the Ascent graph would be way below all of those curves, even if corrected from 11.5 to 13.5 cSt.
Yes, I remember you posting that info. The PL14610 fits Subarus and is pretty much the same size as the PureOne and has a 14-18 psi bypass, and it should stay below the bypass pressure, assuming that old flow curve is still relevant to the modern filters.

I do find it odd that the more expensive Purolator Boss filters with full synthetic media are both more restrictive and less efficient than the PureOne. Maybe the trade-off is durability and holding capacity. In the Ascent test, the Boss also only achieved 99% efficiency at 35 micron instead of the claimed 25 micron, which makes me question whether the PurolatorOne actually achieves its 20 micron rating.
 
Yes, I remember you posting that info. The PL14610 fits Subarus and is pretty much the same size as the PureOne and has a 14-18 psi bypass, and it should stay below the bypass pressure, assuming that old flow curve is still relevant to the modern filters.

I do find it odd that the more expensive Purolator Boss filters with full synthetic media are both more restrictive and less efficient than the PureOne. Maybe the trade-off is durability and holding capacity. In the Ascent test, the Boss also only achieved 99% efficiency at 35 micron instead of the claimed 25 micron, which makes me question whether the PurolatorOne actually achieves its 20 micron rating.
Back when that PureOne was tested, the PureOne filters had a lot of media area which helps them flow well - meaning low dP vs flow. Not sure if they still have lots of media area because I haven't used one for years, so haven't cut one open lately and measured the media area.

I'm sure the PureOne efficiency is what Purolator claims at 99% @ 20u. Of course, keep in mind that their ISO 4548-12 efficiency rating is based on their largest spin-on filter, the 30001. See asterisk note at bottom of their website page.


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